Controller for electric motors



March 13, 1828. 1,662,243

6. T. EVANS CONTROLLER FOR ELECTRIC MOTORS Original Filed May 8, 1922 Eff/Lg. 3,

INVENTOR. iw/cww ATTORNEY.

Patented Mar. 13, 1928.

PATENT orrica.

NITED STATES CLARENCE '1. EVANS, OI MILWAUKEE, WISCONSIN, ASSIGNOB TO THE CUTLER-HAM- HEB MFG. 00., -01 MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

CONTROLLER FOR Application filed Kay 8, 1922,8er1a1 This invention relates to controllers for electric motors, particularly direct current motors.

More particularly the invention relates to 5 controllers of that ty e disclosed in my coending application, gerial No. 283,087, filed arch 1?, i922, which has matured into Patent No. 1,459,033, issued Jan. 1, 1924, to the Cutler-Hammer Mfg. 00., of Milwaukee,

!9 Wisconsin, a corporation of Wisconsin, as

assignee wherein means are provided to insure delayed accelerating operation. The controller therein disclosed comprises jaccelerating switches havin lockout windings and one or more trans ormers to be connected in circuit with the controlled motor to supply transient currents to thelockout windings of the accelerating switches as a function of the variations in motor current incident to acceleration and to other current variations due to commutations of the motor connections without dependence upon the peaks in motor current. The controller thus affords a definite minimum delay incident to each step of acceleration such delay being augmented by the surge in motor current incident to the previous step of acceleration or initial completion of the motor circuit as the case may be.

The present invention has among its objects to provide a simplified controller of the aforesaid character.

A further object is to provide a controller wherein a minimum number of inductive windings are required, and wherein such windings if arrangedin a mutually inductive relation may be used alternately as primary and secondary.

Another object is to provide a controller of the aforesaid character wherein the desired sequence of operation of the accelerating switches may be insured without employment of the usual interlocking contacts.

Various other objects and advantages of the invention will hereinafter a pear.

The accompanying drawings il ustrate certain embodiments of the invention. which will now be described, it being understood that the embodiments illustrated are susceptible of various modifications without departing from the scope of the appended claims.

In the accompanying drawings,

Figure l is a diagrammatic view ,of the prezferred of controller;

ELECTRIC MOTORS.

no. 559,1s7. nenewea August 4, i924.

Referring to Fig. 1 of the drawings the 1 controller is employed in connection with a direct current motor M having an arma-' ture a and a shunt field winding 7. However, it is to be understood thatthe motor might be of any other preferred type.

This controller includes a main switch 1 to connect the motor armature across the lines L and L through starting resistances R, R, R and R in series, it bein understood that the main switch 1 which is shown as single pole may be replaced by a double pole switch or a' pair of reversing switches and that any number of starting resistances may be employed. Also the controller includes switches 2, 3, 4. and 5 to shunt resistances R, R, R and B res ectively.

Each of the resistance contro lin switches is illustrated as of the so-called loc out type being provided with a shunt operating winding w and a lookout winding 3 The shunt windings of' the several switches are arranged to be connected across the line in parallel by auxiliary contacts 1 of the main switch upon closure of the latter switch to I complete the motor circuit. Accordingly all of the resistance switches tend to respond upon completion of the motor circuit but switches 3, 4 and 5 have their lockout windings normally energized to effect positive lockout thereof. More particularly each of switches 3, 4 and 5 as shown has its lock out windin in parallel with the resistance controlled y the preceding accelerating switch and each of said lockout windings is so proportioned relativel to its respective parallel resistance that t e drop across the latter when included in series with the motor will insure adequate energization of the former for lockout action thereof. Accordingly res onse of each of switches 3, 4 and 5 is positively prevented until closure of the preceding switch to shunt thestep of re sistance paralleling its respective lockout winding whereby sequential operation of the accelerating switches isinsured without requirement of the usual interlocking contacts. In this connection it is to be noted that the lookout windin s of switches 3, 4.- 5 might be connec in series with re- I i i r respectively adapted to be short-circuited by auxiliary 3 and 4 respectively.

' What I claim as new and desire to secure 5 by Letters Patent is:

1. In a motor controller, in combination, accelerating means, and means to arrest for temporary periods the accelerating action of the former means in different stages thereofl the latter means including inductive windings and commutateble connections providing for inclusion of said windings in circuit eitei'nsteiy es acceleration progresses.

2 In s motor controller the combination W with scceiersting switches to be operated in sequence said switches havin individual iocitout cofis of inductive windings to so respectively transient currents to t e iochout coiis of difieient switches, and comconnections for said windings pro is ciusion thereof citei'noteiy in otor c cnit ss ccceieirstion progresses. contioiiei, combination ond means to arrest for sns in diii'ercnt stages thereof,

1 i nding windings or t relation and commutiieceifoc to csuse the some e noon the other as the of the mentioned 9 combination, :1 moons to sweet ioc sccciei: tictionoi rent thereof, tiing orand circuit t by said consc windings to othcc succombination o to arrest foi ooceiesotit action of heroin; s" ges thereof, ndings on ve reiotion and commocombination oi'rest the moons in moons inocogi'esses t ts oy solo.

' nation it n opemicie contacts 3 and 4 of switches ov iods the accelerating action of uentially, said switches having individual 66 ikout coils and inductive means to supply transient currents to the lookout coils of said switches, said means including windings respectively connected to the lockout coils of different accelerating switches and. commutatable connections for said windings to cause either to act inductively on the other for energization of the lockout coii connected to the latter.

8. In a motor controller in combination accelerating switches to operate seqnentiallfir, s

said switches having individusi iOQiKOlll) coi and inductivemeans to sunply transient currents to said lockout coiis, said inclsd= ing windings arranged in on ve ireis- 8% tion and respectively connected to he loci:- out coils of different accelersti' s said windings being suhjected -.stcly to the motor current to set olteinsteiy one ii -ion the other 7 9. in a motor controliezc in co obinotion resistance for the motor circuit s ti'oiiing said resistance "ion soc the motor switches hm lockout coils coordinated wi once to deny operation C61 switches pending operation of ct some and mesns inciudin o supply said coils tcorcsi ct further delay operation switches.

L nisiity toi to he cxci I ccspec s niches cc J resistances c of so id ing s iociton't coii connected to preceding the l Wheneby operation such s cnt upon operation 1&5 soid switches moons in not to so: oiy o transient lockout coil oi cici switch to o cerstion thcrecm ill in o motor @@L t) glocsiity o 38 is nces to be circuit sequ d'ilei'ent TESllStfil'lCES; h .ving lockout coi 1 but one of s connected to pififiit" the switc 1315 of? c;- h

" o lo lzont coiis Y n n "a windings is included in circuit'to transient currents.

13. In a controller, in combination, progressively operable switches and. arresting 6 means for said switches comprising inductive windings and commutatable connections whereby first one and then the other winding is included in circuit to supply transient currents and whereby 'the main and induced w currents traversing each winding pass therethrou h in the same direction.

14. n a controller, in combination, a switch having a restrain' windin commutatable connections to an ject sai winding to a current for prolonged delay in operation of said switch and means including a transformer whereby said winding is subjected-to a transient current inductively derived from the former current upon commutation of said connections.

15. In combination, a motor, an accelerating switch having a restraining winding temporarily subjected to motor current and means including a transformer whereby said winding is insured supply of a transient current inductively derived from the motor current for further restraint of said switch.

16. The combination with an electric motor, of a resistance therefor to be. excluded in so etc and means for encluding a step oi" said resistance and then excluding another step instantaneous value of the motor current, said means including an electromagnet conas nested in shunt with the first mentioned step of resistance to he ener 'zed by motor current and to be excluded from circuit together with its parallel step of resistance and said means further including an electrorespon- 4o sive accelerating switch responsive to exclude the second mentioned step of resistance sub ect to delay only by the aforementioned electromagnet.

17.. The combination with an electric 5 motor, of a resistance therefor, means to complete the motor circuit'through said resistance and to thereafter short circuit one step of said resistance and then another step thereof after. a temporary delay regardless 60 of the instantaneous value of motor current,

said means comprising an electrorcsponsive after a temporary delay regardless of the incense switch to short circuit the second-mentioned step of resistance and further comprising inductive time limit control means ,includin an electromagnet connected in parallel wit the first mentioned etc of resistance to be short circuited therewit said electrores on 'sive switch being operable subject to elay niagnet'by motor current and for exclusion of each from circuit together with its parallel step ofresistance and said means t'urther including electro-responsiye accelerating switches certain of which areeach responsive to short circuit one step i-of resistancesubject to delay only by thatloneof the electromagnets aforementioned .avhich is connected in shunt with a' previously short-circuited step'of resistance. I a

19. The combination with an electric n10 tor, of a. resistance therei'or, means to complete the motor circuit through saidiresistance and electro esponsive. accelerating means to short-circa tsaid resistance in steps and to short-circuit each of certain of said steps of resistance after a temporarydelay regardless of the instantaneous value of the motor current, said accelerating means com prising accelerating switchesto short-circuit said steps of resistance and further compris- 1 ing inductive time limit control means includin electrcmagnets connected in, parallel to di erent steps of resistance to be shortcircuited therewith, certain of said acceleratin switches being operable subject to delay 0 y through the medium of one of the electromagnets aforementioned which is in a parallel with a preceding step of'resistanoe,- In witness whereof, I have hereunto subm0; scribed my name. T

CLARENCE :T. EVANS. 

